The Canaries will be hoping to lift themselves off the foot of the Premier League table this weekend, but they will need to secure a result against the Red Devils in order to do that.
During his pre-match press conference the Norwich City boss spoke about the fitness of his team, admitting there are some Covid-19 concerns.
"I cannot tell you any names obviously but there is three or four players at the moment we are waiting on," Smith confirmed.
"There is a couple of players we were worried about so we have tested and we are waiting for the PCR results to come back on them. They have been feeling a little unwell, not likely to be linked with the game last week at Tottenham."
It remains to be seen whether or not the Canaries will have a full squad when they compete against Manchester United this weekend.